I'm looking to have the beginning of the bottom equation aligned with the beginning of the top equation. Similarly, I would like to have all the "for"s aligned, so the bottom ones aligned with the top ones too. What's the best way to do this?
Thanks in advance!
\documentclass[a4paper,12pt,default,numbered,print,index]{article}
\usepackage{lipsum}
\usepackage{enumitem}
\usepackage{graphicx} % Required for the inclusion of images
\usepackage{setspace} % for use of \singlespacing and \doublespacing
\usepackage{pdfpages}
\usepackage{cite}
\usepackage[section]{placeins}
\usepackage{comment}
\usepackage{siunitx}
\usepackage{color}
\usepackage{ragged2e}
\usepackage{esvect}
\usepackage{mathtools}
\usepackage{lscape}
\usepackage{tabularx}
\usepackage{multirow}
\usepackage{array}
\usepackage{soul}
\usepackage{bm}
\usepackage{url}
\usepackage{xparse}
\usepackage{hyperref}
\begin{document}
\begin{equation}
\frac{p'}{\gamma \bar{p}}\Bigg|_d(x,t) \approx
\begin{cases}
(P_d^+ + P_d^-R_1e^{-2\alpha(L_1 + x)})(1 + R_2e^{-2\alpha(L_2 - x)})\\ \times \dfrac{1- (R_1R_2e^{-2\alpha L})^{\lfloor (t + T)/T\rfloor}}{1-R_1R_2e^{-2\alpha L}}
& \text{for}\enspace t \in [0,t_p]
\\
2P_D(R_1R_2e^{-2\alpha L})^{\lfloor (t - t_p + T)/T\rfloor}
& \text{for}\enspace t \in ] t_p, +\infty[.
\end{cases}
\end{equation}
\begin{equation}
\frac{p'}{\gamma \bar{p}}\Bigg|_i(x,t) \approx
\begin{cases}
P_i^+(1 + ^-R_1e^{-2\alpha(L_1 + x)}) \\ \times \dfrac{1- (R_1R_2e^{-2\alpha L})^{\lfloor (t - \tau_c + T)/T\rfloor}}{1-R_1R_2e^{-2\alpha L}}
& \text{for}\enspace t \in [0,t_p]
\\
2P_I(R_1R_2e^{-2\alpha L})^{\lfloor (t - t_p - \tau_c + T)/T\rfloor}
& \text{for}\enspace t \in ] t_p, +\infty[.
\end{cases}
\end{equation}
\end{document}
[12pt]
in the code example doesn't match the original, since the output from the example doesn't have enough space for the equation number on the first equation to fit where it's shown in the output example; and (2) the spacing between\in
and the "open"]
is bad -- this is a case where\left] ... \right[
is necessary. – barbara beeton Aug 25 '17 at 21:10]...[
. if i remember correctly (it's been a long time), that indicates an "open interval", so maybe creating a command\openinterval
that puts in the\left]
and\right[
around an argument would even make the input easier to read (if a bit longer to type). – barbara beeton Aug 25 '17 at 23:42